docs: def payload_unregister(klass, pid):
      """ is used while a hook is running to let Juju know
      that a payload has been manually stopped. The <class> and <id> provided
      must match a payload that has been previously registered with juju using
      payload-register."""
      cmd = ['payload-unregister']
      for x in [klass, pid]:
          cmd.append(x)
      subprocess.check_call(cmd)